English

Von Neumann's inequality for commuting weighted shifts

Functional Analysis 2020-09-21 v2 Operator Algebras

Abstract

We show that every multivariable contractive weighted shift dilates to a tuple of commuting unitaries, and hence satisfies von Neumann's inequality. This answers a question of Lubin and Shields. We also exhibit a closely related 33-tuple of commuting contractions, similar to Parrott's example, which does not dilate to a 33-tuple of commuting unitaries.

Keywords

Cite

@article{arxiv.1508.01260,
  title  = {Von Neumann's inequality for commuting weighted shifts},
  author = {Michael Hartz},
  journal= {arXiv preprint arXiv:1508.01260},
  year   = {2020}
}

Comments

13 pages; minor changes